1. Field of the Invention
The present invention relates to an optical apparatus, more specifically relates to a structure of a flexible printed wiring board which is connected to a movable electrical component provided in an optical apparatus.
2. Description of the Related Art
A flexible printed wiring board is commonly used to electrically connect a movable electrical component to a stationary board such as a stationary circuit board. In many cases, a clearance is given to the length of the flexible printed wiring board in the direction of movement of the electrical component to reduce a resistance (or frictional resistance) in the flexible printed wiring board to movements of the electrical component by drawing or folding the flexible printed wiring board when the electrical component moves.
However, if the motion of the electrical component is not a simple linear motion in one direction, e.g., if the electrical component is movable in not only the longitudinal direction (lengthwise direction) of a long and narrow flexible printed wiring board but also the widthwise direction thereof, the flexible printed wiring board may be acted upon by a force which twists the flexible printed wiring board in the widthwise direction thereof to thereby increase the aforementioned resistance. If this resistance is great, it exerts a harmful effect on the driving accuracy of the electrical component, and the loads on motors and actuators for the electrical component increase. To reduce such a resistance in the flexible printed wiring board to movements of the electrical component, it is conceivable to increase flexibility of the flexible printed wiring board itself. However, the production cost of the flexible printed wiring board itself increases as the flexible printed wiring board is made of a material having a greater flexibility.
For instance, the assignee of the present invention has proposed a type of optical apparatus in United States Patent Publication No. US-2006-0115261-A1 (U.S. patent application Ser. No. 11/289,602), in which image shake of an object image formed on an image pickup device is counteracted by movements of the image pickup device. However, in this type of optical apparatus, since the image pickup device, which is an electrical component, is moved in different directions in a plane orthogonal to an optical axis, it is necessary to consider a resistance such as the aforementioned resistance in the flexible printed wiring board to movements of the image pickup device in the widthwise direction of the flexible printed wiring board. Specifically, the number of conductor traces contained in the flexible printed wiring board tends to be greater to thereby cause a widening of the flexible printed wiring board as the number of pixels of the image pickup device increases, and accordingly, it is desirable to reduce the aforementioned resistance to a minimum even in the case of adopting a wide flexible printed wiring board.